Humidification of inspired gas is a standard practice in the care of mechanically ventilated patients, particularly where the upper airway is bypassed. Humidification may prevent various conditions, e.g., hypothermia, inspissation of airway secretions, destruction of airway epithelium, and atelectasis.
Humidifiers can be passive or active. Passive humidifiers (e.g., a heat-and-moisture exchanger (HME), which may be referred to as an “artificial nose”) may trap heat and humidity from the patient's exhaled gas and return some of the trapped heat and humidity to the patient during the subsequent inhalation. Active, or heated, humidifiers typically pass the inspired gas through or over a heated water bath to increase the heat and water vapor content of the inspired gas. An example of a prior art heated humidifier 2 is shown in FIG. 1.
A common problem with heated humidifiers is liquid spillage. If the humidifier is tilted (sometimes even at a relatively small angle), water may spill through or out of one or more openings or junctions in the humidifier container. For example, in the prior art configuration shown in FIG. 1, if humidifier 2 is tilted, water may spill through openings 4 and/or 5 and into gas delivery conduits 6 and/or 8, which may be undesirable. If water spills into conduit 8, the patient may aspirate the water, which may be undesirable. Spilled water may also damage electronics or other components of the humidifier or apparatus to which the humidifier is attached (e.g., a ventilator).